"We are not immune, but we are not helpless," he continued. "We are not at the mercy of fanatics who slaughter anyone who does not submit to their radical, violent ideology."

It's why the government acted to toughen laws in the wake of the October attacks in Quebec and Parliament Hill, he said, to defend against threats the country faces "every day."

The Conservative leader's voice rose in volume and intensity. Harper picked up his pace as he came firmly to the conclusion of the thought.

"And that is why the Canadian Armed Forces are proudly participating in the international coalition against ISIS."

The crowd there in the Sault erupted in applause. There were whistles and cheers.

Harper's stump speech is filled with these sorts of observations about what the party terms "the security of our country."

"We are in a dangerous world, an ever more dangerous world," Harper warned sternly. And only a Conservative government is going to keep Canadians safe, he said.

Double-barrelled script

The message is deliberate. It's repeated before the crowds at every gathering, part of the double-barrelled script Tory planners have devised for their campaign. The election is about security, they suggest, of the economy and of the country.

"When the most violent and barbaric people in the world, brag about their mass murders … film their murders and put them on international internet TV, when they threaten to do the same thing to Canada and Canadians, we are not going to back down."

In listening to Harper tell this story, the menace seems real. Imminent, even, and on the way to Sault Ste. Marie. And the other guys can't even see it.

"Thomas Mulcair and Justin Trudeau are so wrapped up in some form of twisted form of political correctness that they won't even call jihadist terrorism what it is," Harper scoffed to the crowd, before wrapping it all up.

"If you cannot even bring yourself to call jihadist terrorism what it is, then you cannot be trusted to confront it, and you cannot be trusted to keep Canadians safe from it."

At this, Harper received his most enthusiastic response from the crowd, which erupted into an ovation and calls of "Four more years. Four more years."

Fear, of course, is a powerful motivator. And the horrors and brutal excesses of the so-called Islamic State are indeed fearsome. ISIS militants have massacred innocents in horrible ways, and done it on camera for the world to see.

The Conservative Party knows voters are seeing those videos, perhaps even seeking them out.

ISIS is not the Taliban

Trudeau has pledged to end Canada's bombing campaign in Iraq and Syria.

Harper, on the other hand, has pledged to continue it until the anti-ISIS coalition prevails.

A senior Conservative campaign adviser in a quiet chat Wednesday said its anti-ISIS political messaging is popular with Canadians.

He said the party has research that suggests it resonates particularly well with female voters who, the adviser said, were concerned about the hatred and violence ISIS and its supporters preach.

Canada fought a hard war for years against the Taliban in Afghanistan, sending thousands of soldiers into the fray. But that war did not become the key message of a campaign. By contrast, the Conservative government dispatched 69 trainers to Iraq and has sent aircraft to fight in the coalition war against ISIS.

The Conservative adviser said the two are different. No one expected the Taliban would take their fight to Canada. But that's not the case with ISIS.

Although its forces are not likely to be headed for Canadian shores, the adviser says there are sympathizers who may be compelled to act here, as happened in those two attacks last October in Ottawa and Saint-Jean-sur-Richelieu.

It's that fear the Conservatives are connecting with in places like Sault Ste. Marie, where the loudest applause was in response to Harper's security message: "Only our Conservative Party is going to keep Canadians safe."

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